The invention relates to a device for regulating the traveling speed of a motor vehicle by means of an electric regulator which compares the prevailing actual speed with a desired rated speed and in response to a deviation of the actual or instantaneous speed from the desired speed gives a signal that depends upon the magnitude of the said deviation to a control stage which controls the proportion of the fuel-air mixture supplied to the vehicle's engine.
In known devices of this kind, speed variations of several kilometers per hour occur in the regulated traveling operation, i.e., the vehicle does not move with a constant speed but with a speed that fluctuates about an average set value. This fluctuation can be reduced by an enlargement of the P band of the regulator, to a no longer disturbing quantity, but thereby the regulator becomes as a whole less sensitive, so that in the case of load variations, as those resulting, e.g., from variations of the road conditions, a greater deviation of the actual value from the rated or desired value occurs, which is undesirable. To avoid this, a certain maximum deviation of the actual speed about an average set or adjusted value has hitherto been deemed acceptable.